Over the years Amazon has made it increasingly hard to distribute Kindle format books for people who opt out of total Amazon lock-in. See e.g. this article. I’ve poured a lot of research and effort into creating Kindle-compatible files, only to have Amazon repeatedly move the bar.
If you’re having trouble viewing one of my books on a Kindle device, my recommendation is that you take the EPUB version and use one of Amazon’s approved tools to create your own personal .mobi file from it. I am prevented by Amazon’s licensing terms from doing this myself and distributing the result.
A lot of people have said to me “but so-and-so’s ebooks work just fine!” In my experience, this is usually because a) they are using a publisher (or hosted self-publishing service) that has its own special agreement with Amazon. Or b) because they are using Amazon’s tools outside the licensing terms, something I refuse to do. (Many popular open-source ebook toolchains use Amazon’s tools without regard for the licensing limitations on redistributing the resulting files.)
At some point, I will be re-surveying the field of open, non-license-encumbered tools to see if there are some improvements and updates that can be made to the .mobi files that are part of my ebook bundles. But I honestly don’t know when I’ll have the time.
I’m sorry I can’t be of more help on this!